That's because Greek yogurt is a "strained" version of the dairy product, meaning it's been stripped of whey, a watery byproduct. All that excess whey — known as "acid whey" because of its high level of acidity — isn't necessarily dangerous in itself. However, it's incredibly difficult to dispose of because simply dumping it could lead to serious consequences.

Not only would that be illegal, but whey decomposition is toxic to the natural environment, robbing oxygen from streams and rivers. That could turn a waterway into what one expert calls a "dead sea," destroying aquatic life over potentially large areas. Spills of cheese whey, a cousin of Greek yogurt whey, have killed tens of thousands of fish around the country in recent years. [Modern Farmer]

The booming Greek yogurt industry has exacerbated the problem, since it's now churning out too much whey, way too fast.

Greek yogurt is considered much healthier than its traditional counterpart. It has twice the protein content, and it's lower in lactose, or milk sugar, meaning it fills you up without packing on empty calories.

As a result, Greek yogurt has become a $2 billion industry that has rapidly begun to eat away at the overall yogurt market. Last year, Greek yogurt accounted for 35 percent of all yogurt sales, up from just 1 percent in 2007, according to market research firm Packaged Facts.

Yet with those increased sales have come increased waste. Tons of it. New York, which produces more Greek yogurt than any other state in the nation, produced 66 million gallons of acid whey in 2011 alone.

Andrew Novakovic, a professor of agricultural economics at Cornell University, elaborated on that point in an interview with Businessweek. Using an analogy about dumping food scraps in a river, he explained that while acid whey isn't problematic in small quantities, it can wreak havoc when dumped en masse.

"It's not that apple peelings are going to kill you," he said, "but natural systems like a river can only handle so much foreign biological material."

According to a report from the United Nations' Food and Agriculture Organization, whey is a "strong pollutant" when dumped into streams in large quantities. By its estimate, a cheese factory that processes roughly 26,400 gallons of milk per day would produce the same amount of pollution as a city of 60,000 people.